Ether was originally used as a solvent and chemical reagent, but it also has a strange side effect: inhaling its vapor can... moreEther was originally used as a solvent and chemical reagent, but it also has a strange side effect: inhaling its vapor can cause a feeling of euphoria and even hallucinations. As a result, ether became a popular recreational drug in the 18th and 19th centuries, especially in Europe and the United States.